1. Field of the Invention
The present invention relates to a method of manufacturing a high saturation magnetic flux density alloy thin film for use in a magnetic head for reproducing high density magnetic recording.
2. Description of the Related Art
The material of magnetic heads must have high saturated magnetic flux density (Bs) so as to be suitable for use with a recording medium having large coercive force (Hc) required for performing high density magnetic recording. However, only an Ni-Fe alloy (permalloy) of Bs=about 9000 Gauss has heretofore been available as a soft magnetic material having high Bs value for use in a thin film magnetic head that can be manufactured by an electrodepositing method through a low temperature process with an excellent pattern accuracy. However, in order to improve the magnetic recording reproducing efficiency, a thin film has been desired which has a larger Bs Value, which also exhibits excellent soft magnetic characteristics, and which can be manufactured by the electrodeposition method so as to obtain advantages similar to those of the permalloy film.
An Fe-Co-Ni ternary alloy thin film has an excellent Bs value: Bs=10000-21000 Gauss, and excellent soft magnetic properties. However, it has the smallest coercive force (hc) among alloy compositions having a stable face-centered cubic structure at room temperature. The magnitude of magnetostriction in the vicinity (Bs=18 kG) of Fe.sub.45 Co.sub.20 Ni.sub.35 at which the highest magnetic permeability exists becomes +1.times.10.sup.-5 &gt;0 which is a large absolute value. Therefore, the absolute value of the magnitude of the magnetostriction must be reduced by adding a fourth component.
However, the conditions for manufacturing a quaternary alloy whose main components are Fe, Co and Ni by the electrodeposition method have not been found as yet because the electrode potentials of the component ions at the cathode differ from one another.